Timing Second Cutting Grass Hay

When to make second-cutting hay comes down to two questions. When is the right time to harvest, and is there enough tonnage present to be worth the effort? Hay production and harvest are greatly affected by soil moisture, soil temperature, soil fertility, and disease incidence. However, producers also need to consider the influence of Pennsylvania's weather and differing climates. 

When is the right time to harvest for tonnage? 

The question that often comes up for discussion is, "It doesn't look very tall, is it worth cutting?" Typically, the answer is yes, especially if you are past 40 days after your last cutting. As the grass matures, it is subject to more leaf diseases, such as a brown strip or leaf blotch. It is recommended to take the cutting, harvest what is there, add needed fertility for the next cutting, and hope you get some rain to get it growing again. 

Depending on forage quality needs, cutting schedules can range from 30 to 60 days. For this example, let's consider a 45-day mowing schedule between first and second cuttings. This means that a field cut in early June would be ready for second cutting by mid-July. In most cases, delaying cutting more than 60 days will not increase tonnage as much as it will decrease quality and affect third cutting. For this example, delaying second cutting beyond 60 days into mid-August would likely prevent a third cutting of dry hay since it would be pushed back into late September or early October when the days are shorter and hay is more difficult to dry. 

When is the right time to harvest, given the weather? 

There will be a dry period for most farmers at some point in the growing season. For some, it may last only a week or two, and for others, it might continue for weeks. Consider not only the temperatures, but also the humidity and chance of rain on the horizon before mowing. In most cases, weather models are most accurate for short-term forecasts (3- 5 days), but they can't always predict pop-up storms. 

If the weather does not cooperate, and baling dry hay isn't an option, baleage, grazing, or greenchopping may be viable ways to utilize this forage.

What to do during and after the second cutting? 

During the second mowing, do not forget about your cutting height; keep it above 3 or 4 inches. Stubble is even better for the stand longevity and regrowth. It may be tempting to cut lower to increase tonnage, but please resist. During the hottest time of the year, July to August, adequate stubble will provide more solar receptors for the plant, keep the ground cooler, and help conserve soil moisture.

After the dry, hay-making period has passed, and as moisture returns, the plant will put out new growth. It is now recommended to add fertilizer to the fields to promote regrowth. Nitrogen additions after cutting will stimulate growth, yielding a better third harvest. Applying 35 to 50 units of N is more than adequate for a healthy third cutting. Depending on soil test levels, fields could also benefit from additional potassium and sulfur. 

For more information on Forage Varieties, visit Penn State Forage Variety Trials and check out the various performance data from alfalfa, grass, and annual forages.